9400809 Ainley Seabird studies will be conducted in conjunction with a physical oceanographic cruise that will take place in the Amundsen and Bellingshausen seas during February and March 1994. The objectives of the oceanography and design of the cruise track offers an unparalleled opportunity to investigate the region's avifauna, which never before has been described, but more importantly to use a new technique to resolve an apparent inconsistency in the extent to which the pack-ice edge and the Antarctic Slope Front affects pelagic densities of top trophic predators in the Southern Ocean. The cruise constitutes the first modern oceanographic investigation of the Bellingshausen and Amundsen seas, fully one-third of the circumference of Antarctica. Three hypotheses will be tested: (i) when a shelf- break front is present, seabird biomass will be elevated above that of adjacent waters; (ii) the elevated biomass of seabirds at the ice edge is a function of an increase in abundance of the bird's prey in response to increased phytoplankton concentration; and/or (iii) the elevated biomass of seabirds at the ice edge is an artifact of sampling dependent on ship speed and direction relative to that of the birds. Data would complement those taken in the tropical and temperate Pacific, allowing for a better understanding of the adaptations of birds to life in polar regions. Overall, our research results will increase our understanding of how marine birds use wind as an energy source, providing further insight into the environmental factors that structure communities of these top-trophic predators. ***
